// 审计日志按保留天数清理 — 操作审计 / 登录日志 / 终端会话 / 会话命令 // Logan.Li
package auditcleaner

import (
	"encoding/json"
	"fmt"
	"time"

	"ezops/model"

	"gorm.io/gorm"
)

// Result 单次清理统计 // Logan.Li
type Result struct {
	RetentionDays    int       `json:"retention_days"`
	CutoffTime       time.Time `json:"cutoff_time"`
	AuditLogs        int64     `json:"audit_logs"`
	LoginLogs        int64     `json:"login_logs"`
	TerminalSessions int64     `json:"terminal_sessions"`
	SessionCommands  int64     `json:"session_commands"`
	Total            int64     `json:"total"`
}

// SummaryJSON 生成可持久化的摘要 JSON // Logan.Li
func (r Result) SummaryJSON() string {
	b, _ := json.Marshal(r)
	return string(b)
}

// GetRetentionDays 读取当前保留天数，无配置时默认 180 天 // Logan.Li
func GetRetentionDays(db *gorm.DB) int {
	var s model.AuditSettings
	if err := db.First(&s).Error; err != nil || s.RetentionDays <= 0 {
		return 180
	}
	return s.RetentionDays
}

// Run 删除 cutoff 之前的审计相关记录 // Logan.Li
func Run(db *gorm.DB, retentionDays int) (Result, error) {
	if !model.IsValidRetentionDays(retentionDays) {
		return Result{}, fmt.Errorf("无效的保留天数: %d", retentionDays)
	}
	cutoff := time.Now().AddDate(0, 0, -retentionDays)
	res := Result{RetentionDays: retentionDays, CutoffTime: cutoff}

	if r := db.Where("created_at < ?", cutoff).Delete(&model.SessionCommand{}); r.Error != nil {
		return res, r.Error
	} else {
		res.SessionCommands = r.RowsAffected
	}

	if r := db.Where("start_time < ?", cutoff).Delete(&model.TerminalSession{}); r.Error != nil {
		return res, r.Error
	} else {
		res.TerminalSessions = r.RowsAffected
	}

	if r := db.Where("login_at < ?", cutoff).Delete(&model.LoginLog{}); r.Error != nil {
		return res, r.Error
	} else {
		res.LoginLogs = r.RowsAffected
	}

	if r := db.Where("created_at < ?", cutoff).Delete(&model.AuditLog{}); r.Error != nil {
		return res, r.Error
	} else {
		res.AuditLogs = r.RowsAffected
	}

	res.Total = res.AuditLogs + res.LoginLogs + res.TerminalSessions + res.SessionCommands
	return res, nil
}

// RunFromSettings 按库中配置执行清理 // Logan.Li
func RunFromSettings(db *gorm.DB) (Result, error) {
	return Run(db, GetRetentionDays(db))
}